Motor drive assembly for printing press



April 29, 1969 F. NEAL 3,

I MOTOR DRIVE ASSEMBLY FOR PRINTING PRESS Filed Sept. 21, 1967 INVENTOR Frank Neal ATTORNEYS United States Patent 3,440,900 MOTOR DRIVE ASSEMBLY FOR PRINTING PRESS Frank Neal, Green Brook, N.J., assignor to Wood Newspaper Machinery Corporation, Plainfield, N.J., a corporation of Virginia Filed Sept. 21, 1967, Ser. No. 669,566 Int. Cl. F16h 37/06 U.S. Cl. 74-665 5 Claims ABSTRACT OF THE DISCLOSURE A motor drive assembly for a series of printing units wherein each of the units includes a pair of printing couples, the assembly comprising a drive motor for each unit fiaving a drive shaft extending out of the opposite ends thereof, and gear means connecting the opposite ends of the drive shaft to one of the printing couples of the unit.

BACKGROUND OF THE INVENTION Field of the invention.

This invention pertains to a drive assembly for a pair of printing units in which a multicolor printing operation is to be effected on a web passed sequentially through the units. More particularly, the invention relates to a drive assembly for letterpress printing presses. Each unit of the press includes a gear train between the drive motor and printing couples of that unit which is constructed with a reduced number of points of backlash. In this way, high speed printing may be effected with accurate color registration.

Description of the prior art In prior printing operations where a multicolor printing is to be eliected on one side of a web, it is conventional to provide a plurality of separate printing units and to feed the web of paper sequentially through these units. Each of the units includes two printing couples with each of the couples being used for applying a different color of ink to the web. In order to effect an acceptable printing of the four separate colors on the web, it is necessary that each of the printing couples of each of the printing units be maintained in registration. For this purpose, the drive motors for the printing units are conventionally coupled together. In addition, each of the printing couples of a unit are connected together through gearing which in turn connects both couples to the drive for that unit. With this type of construction, the four printing couples of a two unit press, for example, are theoretically connected together for operation in registration with each other. In practice, however, the existence of gear backlash between the meshing gears of the drive assembly tends to disrupt the color registration of the printing and this is particularly true in letterpress printing presses where the printing plates cover only a portion of the plate cylinders to which they are secured. In such presses, the plate cylinders of the printing couples do not have a completely cylindrical outer surface which would be in continuous running engagement with the web being fed between the couple. As the plate cylinders of the press rotate, a backlash action is created between the engaging gears of the drive tending to cause the couples to move out of registration with each other and thus tending to produce a loss of color registration between the units. Machine vibrations contribute to this loss in color registration by accentuating the backlash action between meshing gears.

Not only does the looseness or backlash between any pair of meshing gears tend to cause loss of color registration, registration is also affected by the number of gear connections in each of the gear trains of the drive assem- 3,440,900 Patented Apr. 29, 1969 bly since the backlash between the gear connections produces a. cumulative effect. Accordingly, the greater the number of such connections, the greater will be the total loss of registration between the printing couples. With conventionally constructed drive assemblies, the number of points of backlash between two printing couples of the press sometimes is as high as ten.

Loss of registration between the various printing couples in the conventionally constructed presses described above is also affected by the inclusion of connecting shafts in the drive assembly of the press. Typically, the drive motor for each unit is provided with a single output shaft to which each of the printing couples of that unit is connected via the appropriate gearing. The use of a motor with a single output shaft, however, necessitates the inclusion of a connecting shaft extending between the pair of printing couples of the unit for drivingly connecting them together; and such a shaft, being inherently subject to torsional deflection as it is rotated, also tends to cause the printing couples to move out of registration with each other as the printing operation continues.

Another disadvantage of the conventionally constructed color printing presses described above resides in the positioning of the drive motor for each of the units. Typically, these motors are positioned between the units so as to facilitate the connection of their drive shafts to the gear trains of the units. This arrangement increases the overall space requirements for the printing press, blocks the aisle space that would otherwise exist between the units and limits the adjustability of the press installation.

SUMMARY OF THE INVENTION In accordance with the teaching of the present invention, the construction of the conventional drive assembly used in multicolor printing presses has been improved to permit high speed printing with accurate color registration. With applicant's construction, a minimum number of points of backlash is provided between any two couples of a series of units to lesses the cumulative effect of such backlash on color registration. In addition, the drive units for each printing unit are constructed so as to permit unobstructed access to each side of the printing unit.

Generally, the improved drive assembly of the present invention includes a drive motor for each of the printing units which is positioned between the printing couples of that unit as opposed to being placed in the aisle space between the units. Each drive motor, in turn, includes a drive shaft extending out from both ends of the motor with each end of such shaft connected through gearing to one of the printing couples of the unit. Only two points of gear engagement exist between the drive shaft and each of the plate cylinders of the two printing couples thus producing only four points of backlash between the two printing couples of the unit. Also, the usual connecting shaft connecting the two printing couples together is eliminated. Finally, with applicants construction, the drive motors for the printing units are connected together by way of couplings producing a negligible amount of backlash so that there will also be only four points of backlash in the gear train connecting either of the printing couples of one unit to either of the printing couples of the other unit.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of a four color printing system incorporating the drive assembly of the present invention and FIG. 2 is a schematic view of the drive assembly of the present invention.

3 DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in FIG. 1 the printing system includes a first printing unit 1 through which a web of paper W is fed to effect a printing on one side of the web. This printing will, for example, be a black printing. The web of paper then passes over various guide rolls to a letterpress printing unit 2. This second printing unit includes two printing couples generally designated as 3 and 4 through which the Web of paper is sequentially fed. The printing couple 3 includes a plate cylinder 5 and a cooperating impression cylinder 6 while the printing couple 4 includes a plate cylinder 7 and a cooperating impression cylinder 8.

Each of the printing couples of the printing unit 2 are employed for printing a different color on the side of the web opposite the side on which the black printing was effected in unit 1. After the web passes from the printing unit 2 it is fed to a third letterpress printing unit 2 which includes a pair of printing couples arranged in the same manner as the printing couples of the unit 2. Like reference numerals with the suffix prime are used to designate like parts in the printing unit 2.

For driving each of the printing couples of the two printing units 2 and 2, separate double ended motors 9 and 9 are provided. As shown in FIG. 2, these drive motors are provided with drive shafts 10 and 10, respectively, extending out from the opposite ends of the motors. Since each of the printing units 2 and 2 are identical in construction, a description of the details of the drive assembly for a unit will be made with reference to printing unit 2 with the understanding that the like parts of the printing unit 2 are shown with the same reference numeral followed by the sufiix prime.

Each of the printing couples of the printing unit 2 are connected to the drive motor 9 associated with that unit through means of separate gear trains. As shown in FIG. 2, each plate cylinder 5 and 7 is provided at one end with a gear 11 fixed thereto for rotation about the axis of the associated plate cylinder. Each of these gears 11 is adapted to be drivingly connected to one of a pair of drive gears 2 fixed to the opposite ends of the drive shaft 10 of the motor 9. For this purpose, a pair of connecting shafts 13 is provided. Each of these shafts extends between the plate cylinders of the printing couples and the opposite ends of the drive shaft 10. A gear 14 is fixed to the end of each of the connecting shafts adjacent the plate cylinders in driving engagement with the associated gear 11. At the lower end of each of the connecting shafts, there is provided a gear 15 which is fixed thereto and in meshing engagement with the appropriate gear 12 of the drive shaft 10. With this construction the rotation of the drive shaft 10 will effect rotation of both plate cylinders 5 and 7.

As shown in FIG. 2, the end of the plate cylinder 5 remote from the drive motor 9 is provided with a gear 16 fixed thereto for rotation in meshed engagement with a gear 17 which is in turn fixed to the cooperating impression cylinder 6. Similarly, the plate cylinder and impression cylinder of the printing couple are provided with the gears 18 and 19 for drivingly connecting these two cylinders together.

With the construction as described above it is to be noted that the double-ended motor 9 having the drive shaft 10 extending out its opposite ends avoids the necessity of a connecting shaft for connecting two printing couples 3 and 4 together. Thus, disruption of the registration between these printing couples that would otherwise be caused by the inherent torsional deflection of such a shaft is avoided. Also, with this construction, the two gears 12 on the shaft 10 can be considered as the same point in the gear train for purposes of determining the points of backlash between the printing couples 3 and 4. Accordingly, the number of such points of backlash between the plate cylinder 5 and the plate cylinder 7 of the printing unit 2 can be counted as four. With reference to FIG. 2, these points of backlash are shown at A, B, C and D.

Similarly, in printing unit 2, the points of backlash between the plate cylinder 5 and the plate cylinder 7 are shown at A, B, C and D.

The two drive motors 9 and 9 of the two printing units are coupled together by way of the couplings 20 and 21. These couplings are of the internal-external gear type producing such a negligible amount of backlash that they are of no significance in determining the number of points of backlash between the various printing couples of the two printing units. Thus, any gear 12 or 12 connected to ciiher end of the shafts 10 or 10 may be considered as a single point in the gear train between any two printing couples of the separate printing units thereby maintaining the number of points of backlash between any two printing couples of the press at four. With reference to FIG. 2, the points of backlash between the printing couple 3 of unit 2 and the printing couple 3 of unit 2 are designated at A, B, B, A; those between the printing couple 3 and unit 2 and the printing couple 4 of unit 2 are designated at A, B, C, D; those between the printing couple 4 of unit 2 and the printing couple 3 of unit 2 are designated at D, C, B, A; and finally, the points of backlash between the printing couple 4 of unit 2 and couple 4 of unit 2 are designated at D, C, C, D.

The drive assembly constructed in accordance with the teaching of the present invention enables a satisfactory four color printing operation to be effected at high speed with accurate registration of the various colors. In addition, the positioning of the drive motor for each unit between the printing couples of that unit provides an aisle space between the two printing units and also permits adjustment of the width of this aisle to suit the plant installation requirements.

The above description of the invention has been made with reference to the presently preferred embodiment; however, it is to be understood that various changes may be made thereto without departing from the scope of the invention as set forth in the following claims.

I claim:

1. In a drive assembly for a pair of printing units where each of said units includes two spaced printing couples defined by a plate cylinder and in impression cylinder driven by a single drive motor and the drive motor for one unit is coupled to the drive motor for the other unit, the improvement comprising:

(a) means for mounting the drive motor for each unit between the associated printing couples thereof;

(b) a drive shaft extending out from the opposite ends of each of said drive motors; and

(c) first and second gear means for each of said units connecting the drive motor thereof to said printing couples wherein:

(1) said first gear means of each unit is drivingly connected between one of said couples thereof and one end of the drive shaft of the associated drive motor for that unit, and

(2) said second means of each unit is drivingly connected between the other of said couples thereof and the other end of the drive shaft of said associated drive motor.

2. The improvement in the drive assembly for a pair of printing units according to claim 1 wherein:

(a) the number of gear connections in said first gear means is equal to the number of gear connections in said second gear means.

3. The improvement in the drive assembly for a pair of printing units according to claim 2 wherein:

(a) the number of gear connections in each of said first and second gear means is four.

4. The improvement in the drive assembly for a pair of printing units according to claim 3 wherein the gear means of each of said units for connecting each printing couple thereof to said associated drive motor includes:

(a) a first gear fixed to one end of the plate cylinder of said couple;

(b) a second gear fixed to one of the opposite ends of the drive shaft of the associated drive motor;

(0) a connecting shaft extending between said first gear and said second gear;

(d) a third gear fixed to one end of said connecting shaft in driving engagement with said first gear; and

(e) a fourth gear fixed to the other end of said connecting shaft in driving engagement with said second gear.

5. The improvement in the drive assembly for a pair of printing units according to claim 4 further including:

(a) third gear means for each printing couple of each printing unit drivingly connecting the plate cylinder and cooperating impression cylinder together.

References Cited UNITED STATES PATENTS 2,462,032 2/1949 Wolf 101-180 X 5 2,707,914 5/1955 Harrold 101-183 2,866,407 12/1958 Hackel et a1. 101181 3,084,621 4/1963 Guastavino 101-181 ROBERT M. WALKER, Primary Examiner.

10 LEONARD H. GERIN, Assistant Examiner.

US. Cl. X.R. 

